Sol-Gel Coated Reinforcement Elements for Rubber Adhesion

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Solution Overview

Problem

The challenge lies in achieving effective adhesion between elastomeric matrix materials, such as rubber, and reinforcement elements like textile fibers and metallic cords, particularly in tire manufacturing, where the differing modulus of elasticity and surface chemistry hinder strong bonding, and existing adhesion promoters like RFL dip raise health and environmental concerns.

Innovation Solution

A method involving a sol-gel coating of the reinforcement elements followed by exposure to a low-pressure plasma treatment, which enhances adhesion by creating a more effective sol-gel layer that surpasses the bonding achieved with traditional oven-drying methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional adhesion promoters like RFL dip (resorcinol/formaldehyde mixture) are used to improve adhesion between reinforcement elements and elastomeric matrix, then adhesion strength is improved, but health and environmental safety deteriorates

Engineering Contradiction:
Improveadhesion strengthVSAvoidhealth and environmental safety
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent removes the harmful resorcinol and formaldehyde components from the adhesion promoter composition, replacing them with a sol-gel coating system that achieves equivalent or superior adhesion without the toxic substances. This extraction of harmful elements directly resolves the contradiction between adhesion strength and health/environmental safety.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters of the adhesion promoter from a resorcinol/formaldehyde/latex mixture to a sol-gel precursor composition containing silicon-based compounds and organic modifiers. This parameter change maintains the adhesion function while eliminating the harmful effects of the original chemicals.

Inventive Principle:
Principle #35Parameter changes

2Strength

If sol-gel coating is applied to reinforcement elements to improve adhesion, then adhesion is improved compared to untreated elements, but the adhesion is still insufficient compared to RFL dip treatment

Engineering Contradiction:
Improveadhesion strengthVSAvoidadhesion performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies a preliminary sol-gel coating to the reinforcement element surface before final assembly. This preliminary action modifies the surface chemistry and topology, creating a foundation for enhanced adhesion. The sol-gel layer serves as a preliminary treatment that prepares the surface for optimal bonding with the elastomeric matrix.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite coating structure combining inorganic sol-gel components (silicon oxide network) with organic modifiers. This composite material provides both chemical bonding capability and mechanical interlocking, achieving adhesion performance that surpasses both untreated surfaces and traditional RFL dip treatment while being environmentally friendly.

Inventive Principle:
Principle #40Composite materials

3Strength

If atmospheric pressure plasma is used for surface treatment, then adhesion is improved, but fiber damage increases

Engineering Contradiction:
Improveadhesion strengthVSAvoidfiber integrity
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent changes the plasma treatment parameters from atmospheric pressure to low pressure (vacuum conditions). This parameter change reduces the intensity and penetration depth of plasma treatment, preventing fiber damage while still achieving sufficient surface activation and adhesion improvement. The low-pressure plasma provides controlled surface modification without compromising fiber integrity.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The low-pressure plasma treatment significantly improves the adhesion between the elastomeric matrix and reinforcement elements, outperforming untreated and RFL dip-treated samples, while avoiding the use of resorcinol and formaldehyde, and is applicable to various reinforcement materials including textile and metallic cords.

Implementation Method 1

the reinforcement element is provided with a sol-gel coating

Methodology Applied
Scientific EffectSol-gel process: Gel

Implementation Method 2

a sol-gel coating of the reinforcement elements followed by exposure to a low-pressure plasma treatment

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

the sol-gel-coated reinforcement element is exposed to the action of a low-pressure plasma

Methodology Applied
Scientific EffectPlasma treatment: Plasma

Data Source

PatentEP3259396B1Process to increase the adhesion between a reinforcing element and an elastomerix matrix
Publication Date: 2019.04.10 CONTINENTAL REIFEN DEUTSCHLAND GMBH

AI summary

The invention relates to a method for improving adhesion between a reinforcement element that comprises textile fibers or textile filaments and an elastomer matrix material, in particular uncured rubber, the reinforcement element being provided with a sol-gel coating and the sol-gel coated reinforcement element being exposed to the action of a plasma, in particular a low-pressure plasma.